Dinosaurs from the Early Cretaceous of Gondwanaland are less well known than those of Laurasia and show some intriguing and unexpected differences. Sauropods remained prominent in the southern hemisphere despite their drastic decline in the northern hemisphere. Large ornithopods were more scarce than their northern relatives; small ornithopods were common. Theropods in the South were often from families different from those in the North.
Canadian Museum of Nature
Dinosaurs from northern Africa had sails on their backs, including Ouranosaurus (an iguanodontid), Rebbachisaurus (a sauropod), and Spinosaurus (a theropod). With their wide surface area, these sails would have helped the animals keep cool, particularly if they stood in the shade with breezes blowing by.
Most of Australia's known dinosaurs are from the Early Cretaceous. Because Australia was within the Antarctic Circle, some of its dinosaurs show adaptations to life in seasonal darkness with small size and large eyes. Large Early Cretaceous Australian dinosaurs included the sauropod Austrosaurus, the plant-eater Muttaburrasaurus, and the large meat-eater Rapator. Smaller dinosaurs included the hypsilophodontids Leaellynasaura, Atlascopcosaurus, and Fulgurotherium; the theropod Kakuru; and the armored Minmi. All these dinosaurs are much different than their relatives on other continents.In the early Cretaceous, many new dinosaurs appeared. They also greatly increased in number. During this period, dinosaurs not only maintained but also expanded their "empire."